Overview
Juniper House is a residential regeneration project in Walthamstow, London, delivering 91 new homes, including 50% affordable housing, commercial units, a pre-school nursery play area, public realm improvements, supporting infrastructure, and more.
A key aspect of Juniper House’s architectural language was stone-like elements around the two-storey entrance and halo-effect flying beams. The original specification proposed GRC cladding to achieve the design intent. But as the project developed, this created challenges around cost, programme, weight, fabrication, installation, and interface detailing.
LockMetal worked with the project team to offer a practical alternative: a stone-effect PPC aluminium cladding system designed to replicate the intended appearance while providing a lighter, more controllable, and more buildable facade solution.
Products delivered
LockMetal supplied and installed a coordinated package of stone-effect aluminium facade and balcony elements, including:
• Stone-effect PPC aluminium wall capping
• Stone-effect aluminium cladding to the two-storey entrance feature
• Stone-effect aluminium halo-effect flying beams
• Internal balcony wall cladding systems
• Balcony soffits
• Podium fascias
• Spandrel panels
• Rainwater pipe solutions
Juniper House
The challenge
The challenge was not that the GRC specification was wrong. In fact, the design intent was strong. The issue was that the specified material could lead to practical delivery difficulties.
• GRC can be effective for sculptural or heavily profiled facade elements, but can come with drawbacks: lead times can be very extended, spare parts expensive, coating options limited, panels are fragile, and installation labour-intensive.
• On a busy residential project with multiple trades and workfaces, heavier or more fragile components can affect lifting, storage, sequencing, tolerance management, and interface detailing.
• The substitution needed to retain the intended GRC/precast stone appearance, while providing a robust rainscreen-compatible cladding solution that could be delivered within budget and programme.
• The package also had to satisfy visual requirements already established for the project, so the alternative system needed to protect the architectural intent rather than erode it.
Results
LockMetal helped turn a difficult precast-style facade detail into a beautiful, buildable, and safe aluminium cladding package, supporting the contractor by reducing cost, programme, and installation risk.
The stone-effect aluminium system retained the intended GRC/precast appearance, while providing a lighter, more controllable solution for a live residential project. Designed to the CWCT Standard for walls with ventilated rainscreens, the package addressed requirements around wind resistance, movement, air permeability, water penetration, thermal performance, and interface detailing.
By expanding the original specification, LockMetal helped align the architect’s vision, the contractor’s budget, the site team’s programme requirements, and the client’s need for a durable finished building.
The result was a facade package that met the design intent, satisfied the practical needs of the contractor, and demonstrated how early specialist engagement from a Tier 2 contractor can reduce risk before it reaches site.
Other projects
The solution
LockMetal proposed a visually compelling, stone-effect aluminium alternative that retained the intended appearance of GRC, but improved buildability, tolerance control, and certainty.
• We substituted the original GRC approach with pressed aluminium cassette/tray panels, finished in an Interpon D2525 Sable stone-effect polyester powder coating, with shadow gap or butt-jointed detailing and concealed fixings to maintain continuity.
• The system was designed to replicate the appearance, depth, and solidity of precast stone, while offering the practical benefits of a fabricated aluminium rainscreen approach.
• By using lighter aluminium panels, the project team could reduce the handling, lifting, and installation challenges associated with heavier, more fragile GRC elements.
• A tight +/-1mm non-cumulative setting-out tolerance, with adjustment to achieve zero misalignment on the panel face, helped deliver the seamless, stone-like finish required by the design.
Stone-effect aluminium cladding in place of GRC on a residential regeneration scheme.
Client
Walthamstow Council
Location
Walthamstow, London
Package size
£723k